1. Field of the Invention
This invention relates generally to an apparatus for the rapid curing of resinous materials by application of energy from an external source to excite polymerization in a polymerizable system. More specifically, this invention relates to an apparatus for the rapid curing of dental materials by using light, pressure, pressure and light, or purge, pressure and light.
2. Brief Description of the Related Art
Curing, as used herein, is the processing of a plastic or resinous material from a fluid or soft and compliant state to a permanent hard, durable and solid state. Conventionally, this is accomplished both by the elimination of solvents and by chemical changes involving interlinking of molecules commonly known as polymerization of the material. Of the two, polymerization is the more advantageous since it does not commonly involve dimensional changes and usually produces a substantial increase in the strength of the material. Polymerization is usually caused by the addition of activating chemicals (activators), by irradiation with some form of wave energy, either electric or electromagnetic in nature, or by applying heat, or by a combination thereof.
The prior art curing processes involve many manual steps that can lead to a variety of errors dependent upon the person performing the operation. One such process uses a pressure bowl depicted in FIG. 1. The pressure bowl 10 includes a base 12 having a platform 14 and a glass or plastic dome or cover 16. A work piece to be treated is placed on platform 14 and glass dome 16 is positioned and locked into place by knob 18. Pressure bowl 10 is then manually connected to an air or gas source at inlet 20. Glass cover 16 is tightened and covered with a cloth to prevent light from entering. Pressure bowl 10 is then pressurized for the required amount of time by turning on the air or gas source. When the process is complete, the air nozzle is removed and pressure bowl 10 is transferred to a light curing box. The work piece, still located in pressure bowl 10, is light cured. After the curing process, pressure bowl 10 is removed from the curing box. To remove the work piece, knob 18 must be turned to unlock glass dome 16. If a glaze is to be placed over the work piece, a purging process is typically required to prevent formation of an oxygen inhibition layer. This involves manually purging bowl 10 with an independent gas source comprising a series of two or more repetitions of filling bowl 10 with gas and releasing and thereafter filling with gas a final time and maintaining gas pressure until the light curing process, as described above, is completed. The manual steps involved in the curing procedures described can lead to many problems in the cured restorations including low strength, distorted shape, tacky surface from incomplete purging, and the like.
There remains a need to simplify the curing process without sacrificing the quality of the final restoration. It is desirable to provide a curing unit that produces consistent results.